Intellect devourers resemble glistening brains with four short clawed legs. They are drawn to, and feed on, Intelligence. Illithids breed intellect devourers by transforming the brain of a thrall. The subjected brain grows legs and becomes independent of its original body.
Intellect devourers encountered on the Ravaged Beach have the passive Weakened, lowering Armour Class by 5, Hit Points by 6, and removing Darkvision. However, they can still be dangerous if they group up on a single character.